Dear Watson #1

If you like your Physics and you like your Chemistry,

You will find this puzzle, as easy as can be.

Firstly, from a glass of milk, take what is good for bones.

Second take the metal used to glaze pottery with pretty tones.

Thirdly you might eat me to get your innards on a slide;

Last I am a diode in a “crystal-set” just look inside.

Now put us all together, and thus what can be seen?

A great big head? ; A large white moth? ; A vegetable that’s green?

What am I?

Check Braingle.com for the answer.